Add support for /tableflip command (#12)

[pt2121]

Type of change

• Feature
• Bugfix
• Technical
• Other :

Content

re #12

Motivation and context

(╯°□°）╯︵ ┻━┻

Screenshots / GIFs

Tests

1. Open the composer area
2. Type /t to see a list of commands starting with t
3. Select /tableflip or directly type in the command

Tested devices

• Physical
• Emulator
• OS version(s): API 21 and API 32

Checklist

• Changes has been tested on an Android device or Android emulator with API 21
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com./vector-im/element-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request includes a new file under ./changelog.d. See https://github.com./vector-im/element-android/blob/develop/CONTRIBUTING.md#changelog
• Pull request includes screenshots or videos if containing UI changes
• Pull request includes a sign off
• You've made a self review of your PR
• If you have modified the screen flow, or added new screens to the application, you have updated the test UiAllScreensSanityTest.allScreensTest()

[bmarty]

Thanks for the PR. Just a small remark about the changelog file, else LGTM!

[bmarty]

Thanks for the fast update!